Complementary Metal-Oxide-Semiconductor (CMOS) image sensors (CIS) are used in numerous applications including digital still cameras. In semiconductor technologies, image sensors are used for sensing exposed lights projected towards a semiconductor substrate. Generally, CIS products include a pixel (or pixel array) region and a periphery region. These products utilize an array of active pixels (i.e., image sensor elements or cells) including photodiodes and other elements (e.g., transistors) to convert images into digital data or electrical signals. Each of the photodiodes includes a p-type pinned photodiode and a n-type pinned photodiode to form a pn junction for transforming photons into electrons. Dark current (DC) and white pixel (WP) performance of the photodiodes are affected by various factors.